Many vehicles, such as, for example highway trucks and off-road work machines, use pressurized fluid during their standard operation. The pressurized fluid may be used for any of a number of purposes during the operation of the vehicle. A highway truck, for example, may use pressurized fluid to operate a fuel injection system or a braking system. A work machine, for example, may use pressurized fluid to propel the machine around a work site or to move a work implement.
Each of these vehicles typically includes a pump that generates a flow of pressurized fluid for use during the operation of the vehicle. Often, however, the pressurized fluid requirements of the vehicle fluctuate depending upon the operating conditions of the vehicle. To avoid wasting pressurized fluid when the vehicle requires a relatively low amount of pressurized fluid, the pumps are typically configured to adjust the amount of generated pressurized fluid based on the operating conditions of the vehicle.
One type of pump that may be controlled to generate a variable flow of pressurized fluid is known as a constant displacement variable flow pump. An exemplary constant displacement variable flow pump is described in U.S. Pat. No. 6,035,828 to Anderson et al. The described pump includes a rotatable swashplate that drives a series of pistons through a compression stroke to pressurize an operating fluid. A check valve is associated with each piston. The check valve is configured to open and allow a flow of fluid when the piston pressurizes the fluid to a predetermined pressure level. The pump also includes a metering device that may be adjusted to vary the amount of fluid that is pressurized with each piston stroke. By controlling the position of the metering device, the amount of fluid that is pressurized with each piston stroke may be controlled. Thus, by adjusting the metering device, the flow rate of pressurized fluid generated by the pump may be controlled.
As also shown in U.S. Pat. No. 6,035,828 to Anderson et al., a constant displacement variable flow pump includes a number of moving parts. This type of pump typically requires a complex housing to support each of these components. For example, a typical constant displacement variable flow pump includes a first housing member that supports the rotatable swashplate and associated input shaft. A second housing member, commonly referred to as a barrel, forms the cylinders that receive the pistons. A third housing member may house the check valves and form a pressurized fluid storage cavity. In addition, the pump may include additional housing members to house the metering device components and any additional pump components.
The manufacturing effort required to make the pump housing and the assembly effort required to assemble the pump constitutes a significant portion of the total cost of producing a constant displacement variable flow pump. This total cost may be decreased by reducing the number of housing components and/or increasing the number of functions performed by each housing component.
In addition, the overall size of the pump is determined, at least in part, by the shape and number of the housing components. A pump with a larger overall size is more difficult to position in an engine compartment of a vehicle. A reduction in the number and/or complexity of the pump housing compartments may lead to a reduction in the overall size of the pump.
The hydraulic pump housing of the present disclosure solves one or more of the problems set forth above.